Infrared chemiluminescent composition

ABSTRACT

THIS INVENTION RELATES TO A CHEMILUMINESCENT COMPOSITION WHICH PRODUCES LIGHT IN THE INFRARED REGION OF THE SPECTRUM COMPRISING A HALOGENATING AGENT, AN ORGANIC COMPOUND SUCH AS DIMETHYLDIBENZANTHRONE, 4-CYCLOHEXYLBENZNATHRONE, PYRANTHRONE, 2-KETO-3-METHYL-1,3-DIAZBENZANTHRONE, DIBENZANTHRONE, DIETHYLDIBENZANTHRONE, DIPHENYLDIBENZANTHRONE, CHLOROPHYLL, 3-METHYL - 1,3 - DIAZA-1,9BENZANTHRONE, 3 - BROMOBENZ(DE)ANTHRONE AND VIOLANTHROPE, AN OXIDIZING AGENT AND A POLAR SOLVENT. LIGHT PRODUCED BY THE CHEMILUMINESCENT COMPOSITION, IS INVISIBLE TO THE NACKED EYE BUT MAY BE DETECTED BY THE STATE-OF-THE-ART PHOTO MULTIPLIER DEVICES.

United States Patent 3 590 003 INFRARED CHEMILUiVIIlSESCENT COMPOSITION Robert A. Meyers, Encino, and Christopher S. Foote, Los Angeles, Calif., assignors to TRW Inc., Redondo Beach, Calif.

No Drawing. Filed June 28, 1967, Ser. No. 649,484 Int. Cl. C09k 3/00 US. Cl. 252186 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to chemical mixtures which emit infrared radiation by a chemiluminescent process and which are suitable for marking objects, humans, or animals at night so that the position of the subject may not be determined by the naked eye but only with infrared detecting photo multiplier scopes.

At present, several chemiluminescent compositions are known which emit visible light. For certain applications, these chemiluminescent compositions have draw-backs in that the light produced is visible to the naked eye and may be readily detected by anyone in the vicinity. In situations where it is desired to limit detection to a few observers, light produced in an invisible region of the spectrum is necessary.

Production of an invisible light as contemplated according to this invention, involves the mixing of a halogenating agent, an organic compound and an oxidizing agent in a polar solvent. Generally the halogenating agent and the organic compound are placed in a container and associated with the oxidizing agent in the polar solvent in another container so that thorough mixing may be readily effected upon the occasion of a particular event. Thus, when the particular event occurs, a bright peak of invisible chemiluminescent light is produced within seconds after mixing and gradually diminishes in intensity. 'Remixing of the chemiluminescent material and the oxidizer will reactivate the light to a brilliance somewhat less than the peak brightness from the time before.

Organic compounds employed in this invention may be selected from the group consisting of dibenzanthrone, dimethyldibenzanthrone, diethyldibenzanthrone, violanthrone, diphenyldibenzanthrone, 4 cyclohexylbenzanthrone, pyranthrone, 2-keto-3-methyl 1,3 di-azabenzanthrone, 3-methyl-l,3-diaza-1,9-benzanthrone 3-bromobenz (de)anthrone and chlorophyll. These organic compounds may be mixed with various halogenating agents, a few examples of which may be selected from the group consisting of chlorine, calcium hypochlorite, lithium hypochlori-te, dichlorodimethyl hyantoin, t-butyl hypochlorite, N-bromosuccinimide', N-bromohydantoin, N-bromoacetice amide, 1,3-dibromo-5,5-dimethylhydantoin, and N-iodosuccinimide. When chlorine or bromine is used as the halogenating agent it is preferably dissolved in chloroform to facilitate the ease of handling.

Oxidizing agents used in this invention are generally a peroxide dissolved in a polar solvent. Peroxides which have been found suitable may be selected from the group consisting of hydrogen peroxide, t-butyl peroxide, and benzoyl peroxide. Polar solvents in which the peroxide is dissolved provide a fluid medium for mixing of the solid materials and may be selected from the group consisting of water, methanol, ethanol, dimethylsulfoxide, pyridine, dimethylacetamide, dimethylformamide, and a mixture of 50% water and 50% dimethylformamide.

In order that the handling and application of the chemiluminescent composition may be expedited, the chemiluminescent composition can be encapsulated in small ampules or pellets which can be easily ruptured. These pellets are ampules are thin-walled and may contain two or three sealed compartments in which the various chemiluminescent ingredients are enclosed. Specific configurations of the ampule or pellet may vary widely. In one embodiment, separate pellets or ampules containing the halogenating agent, the organic compound, and the oxidizing agent dissolved in the polar solvent are mixed in reaction ratios so that when a specified number of ampules are broken the ingredients are mixed in approximately stoichiometric amounts. Generally, the constituents are mixed in proportions ranging by weight, 0.01% to 9% of the organic compound; 1% to 50% of the halogenating agent; 1% to 50% of a peroxide oxidizing agent; and the balance comprising a polar solvent.

In another arrangement, the oxidizer and the organic compound and halogenating agent may be encapsulated in separate concentric pellets, i.e., the oxidizing agent may be encapsulated in a small pellet surrounded by the organic agent and halogenating agent in the outer pellet or vice versa. In still another arrangement, the oxidizer, the organic compound and the halogenating agent may be separately encapsulated in a triple compartmented ampule or pellet. The advantage of these last two arrangements is that the stoichiometric amount of material is more likely upon the rupture of the ampule or pellet.

Numerous packaging or encapsulation materials for the oxidizer and chemiluminescent material can be selected from metals, rubber, or plastics. Plastics, such as tetrafiuoroethylene, polycarbonate resins, polyethylene terephthalate, are generally preferred because they are substantially inert with respect to the oxidizer and the chemiluminescent material. Glass or rubber may also be used, however, regardless of the material which is being used, the wall structure and configuration must be such that the containers may be readily ruptured to permit mixing of the oxidizer and the chemiluminescent materials. Thinwalled metal containers are also suitable, however, special precautions must be taken to protect the metal which sometimes reacts with the oxidizer and the chemiluminescent material. Suitable protection for the metal containers may be simply a thin glass or plastic coating inside the container.

Although other packaging means may be employed, the main criterion for the package is that some means is available for mixing the oxidizer and the chemiluminescent material upon the proper occasion or command.

While the chemiluminescent agent and/ or the oxidizing agent can be used in a solid state, gels and viscous glycerine water phases were found to be effective for extending the light emission of the systems through diffusion control. A gelling medium which has been found particularly suitable is Cab-O-sil M-5, manufactured by the Cabot Corporation. Cab-O-sil is a fire-dry pyrogenic silica with a particle size of about 0.015 micron, a surface area of 200 m. /gm., and a bulk density of 2.2 lbs./ft. Water gels made from these active silica are thixotropic so that they thin down and flow when agitated, beaten, or otherwise admitted to a shearing action. Accordingly, the gels set after mixing which assist in the encapsulation of the materials, but upon the ruture of the capsules, a shearing force is produced causing the gels to flow.

In order to obtain the greatest intensity of chemiluminescent activity, a high loading of chemiluminescent material per unit weight of gel is required. Thus, although the highest possible concentration of active ingredients per unit weight of gel would seem to be the most advisable, a high percentage of solid material renders the gel highly viscous and results in a decrease in the diffusion-controlled chemiluminescent reaction rate. Thus, for optimum re sults, a balance must be made between the brightness and the light-emitting duration.

The following examples are submitted to better illustrate the invention.

EXAMPLE I Approximately 0.52 gram of diazabenzanthrone were dispersed in ml. of chloroform and encapsulated in a thin-walled glass ampule. One gram of chlorine was dissolved in ml. of chloroform and sealed in a thinwalled glass ampule. Approximately grams of sodium hydroxide were dissolved in 3 grams of hydrogen peroxide and 50 ml. of water and encapsulated in a thin-walled glass ampule. The three ampules were then sealed in a blue polyethylene bag which would filter out a small visible red component of the chemiluminescent system. The bag was then placed on the floor of a dark room and stepped on. Immediately, an intense infrared signal was emitted.

EXAMPLE II A solution of 300 mg. hydrogen peroxide in 2 ml. water was sealed in a thin glas ampule. The glass ampule together with 100 mg. calcium hypochlorite and 50 mg. dibenzanthrone were sealed in a blue ployethylene bag. The bag was placed on the floor of a dark room, and when stepped on, a bright infrared chemiluminescent light was emitted.

EXAMPLE III A solution of 300 mg. of hydrogen peroxide in 2 ml. of water was sealed in a thin glass ampule. The glass ampule and a solid mixture of 100 mg. lithium hypochlorite and 50 mg. of 3-bromobenz(d,e) anthorne were sealed in a hard gelatin capsule. The capsule was placed on the floor of a dark room, and when stepped on, the gelatin capsule and glass ampule were shattered, causing the contents to spill out and mix, thereby emitting a bright infrared chemiluminescent light for several minutes.

EXAMPLE IV A solution of 400 mg. hydrogen peroxide in 2 ml. of water and 4 ml. of dimethylsulfoxide were sealed in a thin glass ampule. A solid mixture of 100 mg. calcium hypochlorite, 50 mg. of violanthrone, and 200 mg. cuprite were sealed in a polyethylene bag together with the glass ampule. The bag was placed on the floor of a dark room, and when stepped on a, bright infrared chemiluminescent light was emitted. Visible radiation was almost entirely absent due to absorption by the cuprite and re-emission as infrared radiation.

EXAMPLE V A solution of 400 mg. hydrogen peroxide in 2 ml. of Water was sealed in a thin-glass ampule. A solid mixture of 200 mg. lithium hypochlorite and 50 mg. chlorophyll, to-

gether with the glass ampule, were sealed in a blue polyethylene bag. The bag was placed on the floor of a dark room, and when stepped on, a bright infrared chemiluminescent light was emitted.

EXAMPLE VI A solution of 200 mg. hydrogen peroxide in 2 ml. water was sealed in a thin glass ampule. The glass ampule together with 200 mg. N-bromosuccinimide and 15 mg. dibenzanthrone were sealed in a blue polyethylene bag. The bag was placed on the floor of a dark room, and when stepped on, a bright infrared chemiluminescent light was emitted.

It will be evident, modifications and variations may be effected without departing from the scope of present invention.

We claim:

1. An infrared emitting chemiluminescent composition consisting essentially of z (A) a chemiluminescent material containing (i) an organic compound selected from the group consisting of dibenzanthrone; 4 cyclohexylbenzanthrone; pyranthrone; 2-keto-3-methyl-1, 3-dibenzanthrone; 3- methy1-1,3-diazo1, 9-benzanthrone; 3-bromobenz(d, e)anthrone; dimethyldibenzanthrone; diethyldibenzanthrone; diphenyldibenzanthrone; and chlorophyll; and (ii) a halogenating agent selected from the group consisting of chlorine; calcium hypochlorite; lithium hypochlorite; dicholrodimethyl hydrantoin; t-butyl hypochlorite; N-bromosuccinimide; N-bromohydantoin; N-bromoacetamide; 1,3-dibromo-5, S-dimethylhydantoin; and N-iodosuccinimide which produces infrared light upon mixing stoichiometric proportions with (B) a peroxide oxidizing agent selected from the group consisting of hydrogen peroxide; t-butyl peroxide; and benzoyl peroxide dissolved in a polar solvent selected from the group consisting of water; methanol; ethanol; dimethyl sulfoxide; pyridine; dimethyl acetamide; and dimethylformamide.

2. An infrared emitting chemiluminescent composition consisting essentially of:

(A) a chemiluminescent material containing 1% to 50% by weight of a halogenating agent selected from the group consisting of chlorine; calcium hypochlorite; lithium hypochlorite; dichlorodimethyl hydantoin; t-butyl hypochlorite; N-bromosuccinimide; N- bromohydantoin; N-bromoacetamide; 1,3-dibromo-5, S-dimethylhydantoin; and N-iodosuccinimide; and 0.01% to 9% by weight of an organic compound selected from the group consisting of dibenzanthrone; 4-cyclohexylbenzanthrone; pyranthrone; 2-keto-3- methyl-1,3-diazabenzanthrone; 3-methyl-1,3-diaza-l, 9-benzanthrone; 3-bromobenz(d,e) anthrone; dimethyldibenzanthrone, diethyldibenzanthrone; diphenyldibenzanthrone; and chlorophyll which produces infrared light upon mixing with (B) 1% to 50% by weight of a peroxide oxidizing agent selected from the group consisting of hydrogen peroxide, t-butyl peroxide, and benzoyl peroxide dissolved in a polar solvent selected from the group consisting of water, dimethylsulfoxide, dimethylacetamide, pyridine, dimethylformamide, methanol, and ethanol.

3. A method of producing an infrared light comprising measuring approximately stoichiometric proportions of (A) a chemiluminescent material containing (i) an organic compound selected from the group consisting of dibenzanthrone; 4-cyclohexylbenzanthrone; pyranthrone; 2-keto-3-methyl 1,3 dibenzanthrone; 3- methyl-1,3-diaza-1,9-benzanthrone; 3 bromobenz(d, e) anthrone; dimethyldibenzanthrone; diethyldibenzanthrone; diphenyldibenzanthrone; and cholrophyll; and (ii) a halogenating agent selected from the group consisting of chlorine; calcium hypochlorite; lithium 6 hypochlorite; dichlorodimethyl hydantoin; t-butyl hy- References Cited pochlorite; N-bromosuccinimide; N-bromohydantoin; 0 0 Nbromoacetamidm 13 dibromo 5 5 dimethylhy Chemical Abstracts, vol. 65 (1966), col. 10457 g h. dantoin; and N-iodosuccinimide; and JOHN WELSH primary Examiner (B) a peroxide oxidizing agent selected from the group 5 consisting of hydrogen peroxide; t-butyl peroxide; and S CL benzoyl peroxide; and 252-1883, 301.3

mixing said measured proportions (A) and (B). 

